1. Field of the Invention
The present invention relates to a substrate manufacturing process, in particular, to a process for manufacturing a substrate with bumps.
2. Description of Related Art
In addition to a substrate and a chip, a conventional package may further include a transition board or external devices. The substrate is generally designed into a double-sided circuit to meet the functional requirement and to avoid short circuit caused by the small gap between contacts. However, in order to meet the functional requirement and to enlarge the gap between the contacts, the number of layers for the substrate is increased accordingly, and as a result, the thickness of the package cannot be reduced. Moreover, the increased layers in the substrate may increase the probability of short circuits. Furthermore, a conventional substrate is electrically connected to external devices through solder balls. However, the conventional solder ball has a thickness of about 350 μm, and the gap between the solder balls is increased to avoid the short circuit problem. As a result, the substrate cannot meet the high density and fine gap requirements.